1. Field of the Invention
This invention relates to a method of determining the weight of stockpiled materials. Specifically, it provides a method of determining the volume and the volume-average bulk density of stockpiled materials, wherefrom the weight of the stockpiled materials may be calculated.
2. Prior Art
Present methods of determining the weight of stockpiles are invasive. One method requires filling a box of known volume with material withdrawn from the pile, weighing, and computing the bulk density. In another method, a hole is scooped from the pile and the hole is lined with plastic and filled with water; from the water quantity and the weight of the material scooped from the pile, the bulk density is calculated. In yet another method, holes are drilled into the pile in an effort to obtain undisturbed samples of the material; the samples are weighed, measured, and the bulk density is computed. None of these methods are entirely satisfactory because they entail large errors in the bulk density determination and great difficulty in handling small particulate matter and any voids among the large, dense, and hard materials and boulders.
The present invention provides a novel, noninvasive method of determining the weight of stockpiled material using microgravity measurements, which overcomes the drawbacks of prior-art techniques. Weight determinations using microgravity measurements have been described in the papers authored by (Butler, D. K., September 1980; Sjostrom, K. J. and Butler, D. K., August 1996; Sjostrom, K. J. and Berry, T., December 1996; and Sjostrom, K. J., August 1997.